Interim Fire Dept. Chaplain Fr. Brian Jordan blesses New York Police Department dogs "Kiefer" and "Atlas," Thursday, Oct. 4, 2001 in New York. Both dogs have been used in rescue and recovery efforts, at the site of the World Trade Center disaster. (AP Photo/Kathy Willens, Pool)

SCHAUMBURG, Ill. — A new study in the Journal of the American Veterinary Medical Association reveals that New York Police Department dogs deployed to the World Trade Center after the terrorist attacks of September 11, 2001, have not experienced any long-term health effects.

The study focuses on 27 dogs that assisted in relief efforts at the site, many of which remained deployed throughout the 37-week cleanup operation. Both short-term and long-term health assessments were conducted.

According to the study, about 63 percent of the dogs had some type of health disorder during the first week, including fatigue, eye irritation, respiratory tract problems, decreased appetite, dehydration and cuts. What surprised the study's authors, however, was that only mild and infrequent health conditions were identified during a five-year follow-up period. None of the dogs, according to the study, was identified as having chronic respiratory tract disease or any type of blood disorder.

Nineteen of the 27 dogs were still alive and apparently healthy five years later. In fact, the five-year mortality rate for the 27 working dogs examined in the study was similar to the rate for a control group of household pets and law enforcement dogs that had not been dispatched to the site.

"The general good health of the dogs studied was an unexpected result," said Philip Fox, DVM, the study's lead author and director of The Caspary Research Institute of The Animal Medical Center in New York City. "The dogs appeared to be unaffected in the long term by their exposure to the smoke, dust and toxins they encountered while working at the World Trade Center site."

The findings are in contrast to some human emergency responders who worked at the site, as various studies have identified increases in the rates of illness and the severity of various symptoms of respiratory tract disease.

The reason that the dogs appeared to suffer so few long-term health conditions may be due to differences between human and animal airways and differences in lung defense mechanisms.